Evaluation of deflection amplification factor for steel buckling restrained braced frames
Evaluation of deflection amplification factor for steel buckling restrained braced frames
复制标题
钢屈曲约束支撑框架挠度放大系数的评估
DOI：
10.1016/j.jobe.2020.101228
复制
发表时间：
2020
影响因子：
6.4
通讯作者：
M. Yakhchalian
中科院分区：
文献类型：
--
作者：
Masood Yakhchalian;N. Asgarkhani;M. Yakhchalian
在抗震规范中常见的基于力的设计方法中，将结构在地震力减小时的位移放大挠度放大系数Cd，以估计非弹性位移。本文对钢结构屈曲约束支撑框架(BRBF)的CD值进行了评估。为此，考虑了6个由2-12层BRBF组成的中低层结构，并进行了非线性动力分析。结果表明，在设计地震作用下，ASCE7推荐的CD值(即Cd=10.0)低估了BRBF中下层的弹塑性最大层间位移比(IMIDR)。此外，采用Cd=5.0时，对中高层建筑上部结构的IMIDR进行了估算，得到了可以接受的结果。因此，应用粒子群优化算法(PSO)，提出了一种新的计算公式，以便更真实地估计设计地震作用下钢质BRBF的IMIDR。结果表明，对于低层结构，考虑顶板位移时，Cd=55.0的推荐值明显低估了非弹性最大顶板倾角比(IMRDR)。另一方面，对于较高的结构，Cd=155.0高估了IMRDR。因此，为了更好地估计IMRDR，提出了另一种利用粒子群算法求解CDRoofin的新方程。此外，还研究了应变硬化率的变化对镉和镉屋顶的影响。在本研究的最后部分，研究了Cd和Cd屋顶对反应修正系数(R)的比值随延性折减系数(Rμ)的变化。
In the common force-based design method prescribed in seismic codes, displacements of a structure under reduced seismic forces are amplified by a deflection amplification factor,Cd, to estimate inelastic displacements. The present study evaluatesCdfor steel buckling restrained braced frames (BRBFs). For this purpose, six low-to mid-rise structures comprising 2- to 12-story BRBFs are considered, and nonlinear dynamic analyses are performed. Results indicate that the recommendedCdby ASCE 7 (i.e.,Cd= 5.0) underestimates the inelastic maximum interstory drift ratio (IMIDR) of lower stories in BRBFs under the design earthquake. Furthermore, estimation of IMIDR in upper stories of mid-rise structures usingCd= 5.0 leads to acceptable results. Therefore, by applying the particle swarm optimization (PSO) algorithm, a new equation is proposed forCdto more realistically estimate IMIDR in steel BRBFs under the design earthquake. In the case of roof displacement, the results show that for low-rise structures the recommended value ofCd= 5.0 significantly underestimates the inelastic maximum roof drift ratio (IMRDR). On the other hand, for taller structuresCd= 5.0 overestimates the IMRDR. Thus, another new equation is proposed using the PSO algorithm forCdRoofin order to better estimate the IMRDR. Moreover, effects of variation in strain hardening ratio onCdandCdRoofare investigated. In the last part of this study, variations of the ratios ofCdandCdRoofto response modification coefficient (R) with ductility reduction factor (Rμ) are investigated.